See how your bias tape is folded in half? One of these halves is more narrow than the other. Place the more narrow side on top: this ensures that the underside is caught even if your fabric is a little bit thick. Make sure the tape is on straight, then sew all the way down your first side.
Fold your bias tape around the corner.
Play with your corner until it looks like a pretty, clean mitred corner on both sides! At this point I like to give it a quick “stay there!” press with the iron… pins don’t do too well since there are too many layers and they just end up shifting things around.
Sew all the way down your next side, starting with the anchoring stitch at your corner. Continue for all four sides!
Taraaaa!
